Lomzha-Bialystok Pocket

The Lomzha-Bialystok Pocket was an encirclement campaign carried out by the German Wehrmacht during Operation Barbarossa in World War II.

German plans
On 22 June 1941, Operation Barbarossa - the German invasion of the Soviet Union - began. The Germans massed large army groups along the Soviet border, and they set several objectives for themselves, hoping to achieve them by mid-July; they sought to capture the city of Minsk and all of the other strongholds (Kaunas, Vilnius, and Brest-Litovsk) along the way. The Soviets also had a large concentration of troops along the border, so the German commander-in-chief, Walther von Brauchitsch, hatched a plan to destroy the Soviet Red Army in one fell swoop. He decided to have Army Group North sweep through Lithuania, captured Kaunas and Vilnius, and form a northern pincer that would attack the Soviet 3rd Army from the north. The northern segment of Army Group Center would hold the line along the Poland-Belarus border, while the southern segment would secure Brest-Litovsk and the Pripet Marshes and form a southern pincer to close the encirclement. The ultimate plan was for the two pincers to join at the town of Mosty in the east, trapping several Soviet corps in a large cauldron that would be reduced in size until its borders stretched from Lomzha in the west to Bialystok in the east. The "Lomzha-Bialystok Pocket" would therefore tie down the majority of Soviet forces guarding the approaches to Minsk, and the Germans would be able to destroy the bulk of the Soviet army.

Preparations
In both the north and south, the German army groups made good progress. On the first day of the operation, Army Group North secured Kaunas, and its VI Armeekorps proceeded south to trap the Soviets in a salient to the east of Suwalki, where Soviets were faced by three German forces at once. Meanwhile, Army Group North's II Armeekorps would clear the lands immediately to the east of Kaunas, which were still in Soviet hands.

In the south, Army Group Center outflanked the Soviet fotress of Brest-Litovsk and advanced into the Pripet Marshes, securing the Dnepr-Bug Canal. The Germans then launcehd an attack on Brest-Litovsk from multiple sides, capturing the fortress, and they proceeded to push the Soviets across the Pina River and towards the Shara River further east. With the Germans advancing to the north and south, while remaining on the defensive in the center, the Soviet 3rd Army began to be outflanked, and the makings of a cauldron were underway. The German 4th Army in the south ground to a halt due to the need to rest and refuel, while German forces in the north were also forced to halt due to supply shortages. However, smaller German forces were sent to initiate the formation of the gap by driving the outlying Soviet forces into a more dense pocket.

Suwalki salient
The first phase of the pocket's creation was the elimination of the salient to the east of Suwalki. Two rifle divisions and two fortified regions were trapped in the salient, and the Germans attacked from all sides. The northernmost Soviet unit, the Soviet 126th Rifle Division, was shattered after the XXXIX Panzer Corps assaulted it. The Germans proceeded to work their way south, attacking the 48th Fortified Region next. The 48th Fortified Region was forced to surrender after another German victory. The German forces closed in tighter on the salient, with Adolf Kuntzen's LVII Panzer Corps attacking the Soviet 128th Rifle Division. The division was shattered, suffering extremely heavy losses. Finally, the Germans assaulted the 68th Fortified Region, and the region's surrender led to the elimination of the salient.

Biebrza line
With the Suwalki salient eliminated and the VI Armeekorps driving deeper into the Soviet pocket, the Germans set out to thin out the Soviet line by capturing a strip of Soviet-defended land across the Biebrza River. The "Biebrza line" stretched from the Narew River in the west to Augustow in the east. The first step in eliminating the bulge was the capture of Augustow, a task undertaken by Walter Heitz's VIII Armeekorps. The Germans secured the town after shattering the 86th NKVD Border Regiment, and German mechanized infantry from the LVII Panzer Corps flowing in to assist the other German units. The swamp to the west of Augustow was captured by the German 162nd Infantry Division, a part of Friedrich Materna's XX Armeekorps, from the Soviet 4th Rifle Corps, which was routed. The XXXXII Armeekorps under Kuntze continued on the offensive, forcing the 66th Fortified Region to surrender. In a rare and early victory for the Soviets, the Soviet 1st Rifle Corps held Grajewo against two German attacks. After repeated ground and air attacks, the Germans finally managed to force the Soviet 2nd Rifle Division to retreat, taking the town of Grajewo. Much the same occurred at Kulmo, where it took several attempts for the Germans to secure the fortress before the Soviets retreated.